The application of satellite radar interferometry to subsidence monitoring in the Belridge and Lost Hills fields, California

Oil production from weak, compactable, and low permeability diatomite oil reservoirs in the Belridge and Lost Hills fields in California has resulted in subsidence. Previous efforts to monitor subsidence in these fields have included the installation of surveyor monuments. These monuments allowed the comparison of repeated elevation measurements at the monument locations and the installation of permanent arrays of tiltmeters to measure the direction of the gravity vector through time. Since late 1998, repeat-pass interferometric synthetic aperture radar (InSAR) data have been operationally acquired from several satellites and evaluated over the Belridge and Lost Hills fields to monitor subsidence. Because of the temporally and spatially dynamic nature of subsidence in these fields, the customer decided to acquire InSAR data sets approximately monthly over both fields to monitor subsidence rate changes caused by field development and operating practices. ERS-2 and Radarsat have been used. It has been possible to measure subsidence rates across each field. InSAR deformation data have been compared to and validated with a series of GPS monument survey measurements.